Introduction & Chapter 1

• presentations:

  • find a marine mammals species and make a 15 min presentation on what it is and all that shit

  • 30% of total grade

  • no more than 15 slides (1 slide per minute) → total 15 min presentation

  • grades on slides and presentations

• written exam: 11th of april

  • mcq

  • short answers

  • long answers

  • 6 questions with sub questions

    • one question can be about one whole chapter

  • 70% of total grade

what is a marine mammal?

• emerged abt 50 million years ago

• more than 132 living species

• main differences between terrestrial and aquatic mammals; the more time they spend in the water, the greater the adaptation to:

  • gas exchange → inability to exchange lung gases at all times

  • increased rate of integumentary heat loss

    • integumentary system includes the skin, hair, and blubber. So when compared to terrestrial mammals, marine mammals lose heat faster to the water compared to terrestrial mammals losing heat to the air, as water is a good conductor for heat. But they adapted to that, e.g. blubber.

  • relative weightlessness

  • greater resistance to movement

  • changed sound propagation

  • low light conditions underwater

cetaceans (fully aquatic)

• consists of 92 species

• two suborders:

  • Mysticetes → 16 species

  • Odontocetes → 76 species

• altogether has 13 (14) families (1 is extinct → yangtze river dolphin)

• can range from 1.2 m to 33 m in length

• varying weights across species

• small to very long lifespans

• can be marine or freshwater

• can be solitary or social

• may migrate or stay in local habitat

• can be found around the world, from the polar caps to the equator

• adaptations:

  • rapid gas exchange - hold breath for a long time

  • thick layer of blubber and vascular heat-exchange system

    • blubber → insulation, energy storage, buoyancy control, streamlining

    • vascular heat-exchange system → uses countercurrent heat exchange to conserve or release heat depending on the environment

  • big sizes support own weight

  • smooth skin, rigid bodies, internal genitalia, lack of hind limbs - reduce drag, strong tails to move, dorsal fins for stability

  • sophisticated sound producing and processing systems

  • low light conditions → echolocation

  • BUT: huge difference among species and groups

Mysticeti - 3 (4) families; 16 species

• these are baleen whales

• Only baleen whales have two blow holes; that’s how to distinguish them from other whales

• the grey whales used to a be a separate family of their own

• characteristics:

  • baleens - filter feeders: gulp feeders, skim feeders, bottom feeders …

  • 2 blowholes

  • large size (largest mammal)

  • females are approximately 5% larger than males

  • streamline bodies

  • solitary mammals

  • long migrations between feeding and breeding grounds

  • low frequency sound production

  • long distance communication

  • no sound transmission in lower jaw (like toothed whales) (bone conduction)

  • functional vomeronasal organ (detects chemicals)

• family Balaenidae - 2 genera, 4 species

  • genus Balaena

    • bowhead whale

  • genus Eubalaena

    • north Atlantic right whale

    • north pacific right whale

    • southern right whale

  • characteristics:

    • arched jawline

    • huge mouth

    • longest baleens = 4 m,

    • feeding by continuous streaming water through open mouth

    • no dorsal fins

    • slow swimmers

    • biggest testis - sperm competition

• Family Neobalaenidae / Cetotheriidae - 1 genus, 1 species

  • pigmy right whale “living fossil”

  • smallest of the ballen whales (6.45 m), sleeker, falcate dorsal fin, arched jawline

  • not well studied, not many sightings, population unknown

• Family Balaenopteridae (Rorquals) - 3 genera, 11 species

  • rorquals “gulp feeders”, ventral grooves, huge tongue

  • genus Balaenoptera

    • blue whale

    • fin whale

    • sei whale

    • bryde’s whale

    • eden’s whale

    • omura’s whale

    • rice’s whale

    • common minke whale

    • southern minke whale

  • genus Megaptera

    • humpback whale - longest flippers “wings”

  • genus Eschrichtius

    • grey whale - bottom feeder, use tongue to suck in food, short strong baleens

    • used to belong to old family called Eschrichtidiidae

Odontocetes - 9 (10) families; 76 species

• characteristics:

  • teeth - feed on fish / squid / warm blooded animals

  • one blow hole (left side) - right blow hole is a sound producing organ

  • echolocation

  • melon head - sound production

  • variable in size, males are larger than females (except some beaked whales, Cephalorhynchus dolphins and porpoises)

  • social group

  • local and migration

• one extinct family → Lipotidae (Yangtze river dolphin)

• Family Physeteridae - 1 genus, 1 species

  • sperm whale → max 18 m long, weighing 60 tonnes

• Family Kogiidae - 1 genus, 2 species

  • pygmy sperm whale → 3.8 m, 500 kg

  • dwarf sperm whale → 2.7 m, 300 kg

• Family Monodontidae - 2 genera, 2 species

  • Narwhal → 3.5 - 5 m, 800 - 1600 kg, male’s tusk 1.5 m long

  • beluga → 3.9-4.8 m, 1.3-1.9 tonnes

• family Ziphiidae - Beaked whales, 6 genera, 22-24 species

  • deep divers, sexual dimorphism (females are larger than males), males teeth are tusk-like (sexual selection features), 4-16 m, 1-15 tons, nomedian notch on fluke (flukes are not like mysticetes)

  • Mesoplodon e.g. strap-toothed whale

  • Ziphius e.g. Cuvier’s beaked whale

  • Berardius e.g. Baird’s beaked whale

  • Tasmacetus e.g. Shepherd’s beaked whale

  • Indopacetuc e.g. tropical bottlenose whale

• family Delphinidae - marine dolphins, 17 genera, 37 species

  • Orcinus - killer whale

  • Globicephala - Long-finned pilot whale

  • Pseudorca - false killer whale

  • Feresa - pygmy killer whale

  • Peponocephala - Melon-headed whale

  • Orcaella - Irrawaddy dolphin

  • Sotalia - Tucuxi

  • Sousa - indo-pacific humpback dolphin

  • Lagenorhynchus - Atlantic white sided dolphin

  • Grampus - Risso’s dolphin

  • Tursiops - bottlenose dolphin

  • Stenella - pantropical spotted dolphin

  • Delphinus - common dolphin

  • Lagenodelphis - Fraser’s dolphin

  • Lissodelphis - Southern right whale dolphin

  • Cephalorhynchus - Commerson’s dolphin

• family Planktanistidae - 1 genus, 1 species

  • south asian river dolphin

• family Iniidae - 1 genus, 1 species

  • amazon river dolphin

  • araguaian river dolphin

  • bolivian river dolphin

• family Lipotidae - 1 genus, 1 species (EXTINCT)

  • yangtze river dolphin

  • died out in 2002

• family Pontoporiidae - 1 genus, 1 species

  • Franciscana (la plate dolphins)

• family Phocoenidae - porpoises, flattened, spade-shape teeth, lack of pronounced beak, 3 genera, 8 species

  • Neophocaena -

    • indo-pacific finless porpoise

    • east asian finless porpoise

    • yangtze finless porpoise

  • phocoenoides -

    • dall’s porpoise

  • Phocoena -

    • harbour porpoise

    • vaquita (nearly extinct)

    • Burmerister’s porpoise

    • spectacled porpoise

sirenians - 4 species, fully aquatic

• characteristics:

  • fully aquatic, herbivorous mammals, with their strong lips pull out seagrass

  • consumes 10-15% of their body weight per day

  • inhabits swamps, rivers estuaries, marine wetlands, and coastal marine waters in North America, South America, Africa, and Asia

  • 2.5 and 4 m, 1,500 kg

  • longevity 50 to 70 years

  • females give birth only a few times during their lives ad invest considerably

  • mothers care for the young

• 2 families:

  • manatees

  • dugongs

• family Dugongidae - 1 genus, 1 species

  • dugong

  • bottom feeders often on seagrass, pointy tails

• family Trichechidae - 1 genus, 3 species

  • African manatee

  • Amazonian manatee

  • west indian manatee

  • plant eater in water column

pinnipeds - (semi-aquatic) 34 species

• 3 families

  • Odobenidae (only living member is the walrus)

  • Otariidae (the eared seals: sea lions and fur seals)

  • Phocidae (the earless seals, or true seals)

• family Odobenidae - 1 genus, 1 species

  • walrus

  • no external ears

  • tingue suction feeders

  • feed on bottom marine organisms

  • male: 3 m, 1200 kg

  • female: 2.2 m, 560 kg

  • populations: Atlantic ocean, pacific ocean, and laptev sea

  • age: 20-30 years

  • migration between ice (pupping) - feeding areas

  • predators: killer whale and polar bears

• family Otariidae - 7 genera, 15 species

  • these are eared seals

  • semi-aquatic lifestyle

  • subpolar, temperate, and equatorial waters in Pacific and Southern Ocean, southern Indian and Atlantic Oceans

  • absent in the north Atlantic

  • less adapted to sea life than phocids

  • can turn hind limbs to walk on land

  • have external ears

  • profound sexual dimorphism (males weigh 2-6 times more than females)

  • shorter and shallower dives

  • subfamily Archtocephaline (fur seals) - 2 genera, 9 species

    • genus Arctocephalus (8 species)

    • genus Callorhinus (1 species)

  • subfamily Otariinae (sea lions) - 5 genera, 6 species

    • genus Eumetopias

    • genus Neophoca

    • genus Otaria

    • genus Phocarctos

    • genus Zalophus

• family Phocidae - 14 genera, 18 species

  • characteristics:

    • no ears

    • mostly aquatic, return to land or pack ice to breen and give birth

    • deep long dives

    • 1.1 - 5.8 m

    • 45 - 5000 kg (male southern elephant seals)

  • subfamily Monachinae - southern seals, 7 genera, 8 species

    • Monachus

    • Neomonachus

    • Mirounga

    • Ommatophoca

    • Lobodon

    • Hydrurga

    • Leptonychotes

  • subfamily Phocinae - northern seals, 7 genera, 10 species

    • Cystophora

    • Erignathus

    • Phoca

    • Pusa

    • Pagophilus

    • Histrophoca

    • Halichoerus

otters (semi-aquatic)

• family Mustelidae - weasels and otters (1 species)

sea otter

• pacific ocean, nearshore water

• males: 22-45 kg, 1.2-1.5 m

• females: 14-33 kg, 1-1.4m

• no blubber but densest thickest fur in the animal kingdom

• although it can walk on land, the sea otter is capable of living exclusively in the ocean

• gives birth in water

• lifespan: males are 10-15 years, females are 15-20 years

eurasian otter (semi-aquatic)

• eurasia, asia, north Africa

• lakes and rivers

• lives along the coast in salt water, but requires regular access to freshwater to clean its fur

• lives in dents on land, close to water

• mating and birth on land

• 57 to 94 cm long, tail of 35-45 cm

• 7-12 kg

• age: 8-13 years

polar bear (semi-aquatic)

• family Ursidae - bears, 1 species

• 19 populations in the arctic, need pack ice to hunt seals

• considered marine mammals because of their dependence on marine ecosystems

• prefer annual sea ice but live on land when ice melts in summer

• males 2-2.5 m, 420-500 kg

• females 1.6-2.5 m, 150-300 kg

• white fur is thick and water repellent, below is black skin

• 5-10 cm blubber layer

• age: 25-30 years

zoogeography

• distribution of marine mammals today, ranges of distribution and migrations

• importance of water temperature as geographical limits

  • prey abundance

  • birthing places

mysticeti - migratory

• polar to equator (most)

• circumpolar (bowhead)

• equatorial (bryde and omura)

• local (humpback and fin population in Mediterranean sea)

• cosmopolitan (blue, fin, sei, humpback)

odontoceti

• some migrate (only males in sperm whales)

• some migrate circumpolar (narwhal and beluga)

• equatorial (some dolphins, short-finned pilot whales)

• anti-tropical (ziphiids, long-finned pilot whales)

• cosmopolitan (killer whales, sperm whales but local populations)

• coastal (porpoises, river dolphins, indo-pacific bottlenose dolphins)

sirenia

• tropical, subtropical dugongs - marine mantaees tied to freshwater

• access to abundant aquatic plants

• coastal areas and river (amazon manatee is entirely freshwater)

sea otter

• north pacific, fragmented due to over exploitation, no resettlement

• nearshore areas due to benthic prey

polar bears

• circumpolar

• close to northern phocid seals, primary prey

• depend on sea since for hunting

otariids

• cool temperature and subpolar

• popping and mating areas close to shore

• absent north Atlantic

phocids

• polar (crabeater seal)

• some non-migratory (ringed seal)

• ice adapted (birth on ice)

• highly migratory (elephant seals)

• freshwater (baikal, caspian seal)

• warm water (monk seall)

odobenids

• distinct northern circumpolar

• due to hunting, the population is reduced